I hope that this can be the right decision.

General Repair of Adobe Acrobat Reader to recover pdf online

But, there are some alternative ways that were found around Internet forums, search engines and etc…

https://helpx.adobe.com/acrobat/kb/quick...

https://helpx.adobe.com/acrobat/kb/troub...

Go to adobe official website, click the "Support" tab on the top of the screen, click on "Adobe Reader," and then select the "I can't open a PDF document" statement underneath "Troubleshooting." The Support tab is located near the top of the screen as a white word against a black backdrop. After clicking Support, you will see the phrase "Product Support Centers" on a new page in bold white font, under which is "Adobe Reader." The new page after clicking "Adobe Reader" will have the word "Troubleshooting" underneath the phrase "Adobe Reader and Help Support." Underneath "Troubleshooting" is "I can't open a PDF document."

Files can be recovered from Adobe Acrobat Reader. There is the official forum from where you can read. But, if you don’t find anything their directly. Then, you can read '''Adobe Acrobat Reader Review.''' You will surely get to know from here.

If you are having issues with PDFs opening incompletely on your phone. This is due to the phone prevents the in browser view of the PDF.

You can bypass this problem by installing a PDF reader application.
OR
You can install a PDF program on your computer so the PDF downloads and opens with no hassle.

Try restarting the phone